Lazy when hot

[Efini]

Finally got my boost pressure to where I want it, 1.6bar peak and 1.4redline on a MTM chip. Still running oem injectors, KN open cone, decat, Forge DV, GT3071R turbo, 034 "RS2" exh.manifold, h-beam rods.

Problem is:
The car is fast, but I'm not impressed. Would imagine that a big turbo whould produce more power on the butt-dyno.
I've treated the engine and turbo with respect since my rebuild and never pushed the car before it was properly warmed up.
Yesterday I could not help but flooring the throttle straight after I started the car, and the car just launched like a missile! I have no words for how fast the car was.
Still with the same boost, only difference; the car engine was cold.
As soon as the engine temp started rising the car went lazy again..
Another problem that might be releated is that when hot the idle is very unstable and the engine sometimes dies on me due to low idle revs. When cold the idle is steady as a rock.

Any theories?

[Jamo]

See Coreys thread about the sick 3B, with MAF relocation required to cure the sympthons you have with low revs

[Efini]

See Coreys thread about the sick 3B, with MAF relocation required to cure the sympthons you have with low revs

Thanks for the tip Jamo, interresting read, might have to try a similar solution and see if it helps.
Also interresting to see that both Ross and Faheemo had the same idle problem after installing the 3071.

I might try to fit the stock airbox again and see if that helps, but I doubt it will fit over the 3071.

[Ross]

I'd be interested to see if you can fit the airbox, as I'm gonna try fitting my RS2 airbox when i put the 3071 in my Avant. Out of interest how did the fitment of the 3071 go in your RS2, did you have to replace engine mounts?

Might be worth trying it to see if it affects you 'lazy when hot' issue as well, as I suspect heat soak could be a problem? Where is the intake pointed to?

Ross

[Efini]

I used a 1cm spacer on the right engine mount and the hotside now clears the chassie by about 0.5cm. Will be replacing the enginemounts later and see how that works out.

Heatsoak might well be a problem as my conefilter is now just mounted straight onto the MAF and straight above the turbo without any heatshielding.
But I would not think that is the entire reason. Because the car gets lazy as soon as the coolant temps start rising. Wouldn't think that heatsoke would be a problem at such an early stage? Had the same problem when outside temps were a freezing -20 celsius.
But I could be wrong, I really have no real idea how badly heatsoke can affect performance.

I will try to fit the airbox now, back in 20 mins.

[Efini]

The RS2 airbox will not fit at all.
The lower mounting tab is pushing against the waterlines and the box itself won't go in because of the big coldside of the turbo.
Might fit with som hacking, but I'm afraid it will involve major modifications.
Someone please prove me wrong.

I've now added some thermal blanketing over the turbo to see if this will help my problems.

[Jamo]

It wont fit without fibreglass remodelling of the box

[philS2]

i've taken my airbox out completly before and noticed heat soak after about five mins,then after i floored it it was way too hot and it hesitated like hell.